Due to the often perilous surroundings and the limited air supplies during deployments with self-contained breathing apparatus, time quickly becomes a critical factor, which can decide between life and death. Communication between firefighters must therefore be clear and quick.
Training and reliable equipment are a prerequisite for interference-free communication when using breathing apparatus. Constant communication within the team also reduces the stress level of the breathing apparatus wearer, strengthens team spirit, and ensures a timely coordination within the team.
During deployments in chemical protective suits, the breathing mask is not the only thing that impairs communication. The suit itself also absorbs the sound of speech, thus making verbal communication possible only via radio. However, this is problematic because it is difficult and time-consuming for the wearer to actually reach the radio underneath the suit, as he has to move his arm out of the sleeve and to the body. To avoid this, the wearer can use a push-to-talk button, which he can feel and operate through the suit.
Constant communication within the team is essential, particularly during deployments involving the use of thermal imaging cameras. The person operating the camera must also inform the firefighter about the current situation and possible hazard points, as he can only depend on his sense of touch in thick smoke. Furthermore, he can inform the operations command by radio about the exact situation.
For over 50 years, manufacturers have been working on communication solutions for use with self-contained breathing apparatus. In Europe, the developments initially concentrated on the breathing apparatus wearer being able to better utilise his radio, in spite of the mask, by means of a headset. On the one hand, speech is to be transmitted to the radio without distortion and on the other, it is to be made easier for the breathing apparatus wearer to follow radio communication by means of an earpiece. Thanks to headsets, breathing apparatus wearers no longer have to take the radio out of a jacket pocket and hold it in their hand, but can send radio messages by operating a push-to-talk button.
The technical difficulties during the development of communication solutions for breathing apparatus applications lie in the fact that speech is absorbed to a great extent by the mask. In addition, the microphone cannot simply be wired to the inside of the mask because the mask must fit snugly and has to be regularly cleaned and disinfected.
Solutions based on scull microphones are easier to realise as they do not interfere with the mask system. Scull microphones pick up the vibrations from the scull, which are generated when a person speaks. They therefore only transmit speech and not ambient noise. Unfortunately, speech quality fluctuates greatly depending on the positioning of the microphone. Creases in the fire safety hood or the mask strapping must not impair contact with the scull. Furthermore, the transmission of higher-pitched voices, for example female firefighters, is noticeably poorer. Thick hair also impairs transmission.
Throat microphones can supply good speech quality when seated correctly. However, due to their cumbersome assembly and troublesome wearing comfort, many firefighters usually reject this type of microphone. Scull microphones and throat microphones are both only available as a headset for connection to radio units. They are not suitable for use in conjunction with voice amplifiers.
Normal airborne-sound microphones, as used in headsets with gooseneck microphones, can pick up damped speech outside the mask. However, they also transmit ambient noise around the breathing apparatus wearer. Communication is thus still possible under office conditions, but can be significantly impaired or even impossible under extreme operational conditions. Furthermore, the gooseneck can get displaced during deployment, so disabling communication.
In the USA and some Asia Pacific countries, the focus for a long time was on transmitting speech to the direct vicinity of the apparatus wearer by means of an electronic voice amplifier in order to facilitate communication. Voice amplifiers can be fitted on certain breathing masks and are battery-operated, but do not substitute for radio communication.
Both development paths not only improve communication, but can also save the firefighter’s life in an emergency. To ensure reliable speech communication in the supreme discipline of self-contained breathing apparatus, Dräger has incorporated both development paths in one product – voice amplifier and radio connection. With the FPS-COM-PLUS communication unit, for example, the firefighter has both a fully integrated voice amplifier and an integrated headset at his disposal. A headset does not have to be put on separately as the unit slips perfectly into place when putting on the mask. The wearer can position the flexible earpiece perfectly in front of his ear so that he can understand incoming radio messages clearly and without delay.
The FPS-COM-PLUS picks up speech directly in the inner mask and can thus reproduce it without interference from the voice amplifier and transmit it to the radio unit. Breathing sounds are almost completely filtered out; the mask screens the microphone from ambient noise. Firefighters can thus even send a radio message at extreme ambient noise levels, which the operation’s command receives loud and clear. By connecting the FPS-COM-PLUS to the radio unit, evacuation alarms cannot be overheard and emergency calls can be made safely even at very high ambient noise levels.
The unit can be connected to a fist microphone, a big push-to-talk button or directly to a radio unit by means of a robust jack plug. When connected directly to the radio unit, the radio unit is activated by an integrated push-to-talk button on the mask.
The FPS-COM-PLUS is ATEX approved for use in explosive areas (Zone 0), EN 136 and EN 137 Type 2. A decisive factor for many fire departments is the fact that the communication solution integrated in the mask not only increases safety in an emergency, but contrary to distress signal units and detectors, reduces stress levels and increases the efficiency of firefighters even in normal daily operations.
For further information, go to www.draeger.com/fire